2009 Buddy 125 misfire at WOT

Bill61 · Post by **Bill61** » Sun Jul 28, 2019 2:15 am

Has a new spark plug. Running with no air cleaner on carburetor. A main jet issue? Valve clearance? What should the clearance be on intake? Exhaust?
Installed new pilot jet, idles great, mid range good also. Thanks for the advice!!
Unfortunately the jet kit I received did have the proper size pilot jets, but the main jets do not fit. The diameter of the threaded part is to big. And they started at a #100. I have a #92 installed now.

scootERIK · Post by **scootERIK** » Sun Jul 28, 2019 2:57 am

You need this type of main jet. - https://www.scooterworks.com/Jet-Keihin ... P6805.aspx

If you are running with no air filter and a #92 jet you are probably super lean. If you keep doing it there is a good chance you will blow the engine.

babblefish · Post by **babblefish** » Sun Jul 28, 2019 3:02 am

What scootERIK said. And if you run an aftermarket foam type air filter you'll have the same problem. You need to rejet for a richer mixture. How much will be determined by experimentation on your part since jet settings can vary depending on where you live. The jets you need are commonly known as Keihin 4mm main jets. Just for reference, I run a #102 in my 150cc Buddy with stock air cleaner. You may also have some issues with the CV working correctly.

Bill61 · Post by **Bill61** » Mon Jul 29, 2019 3:02 am

Great advice all, thanks!! Reinstalled OEM air filter. No misfire at WOT.